Trip report
Feb 17, 2020 — I hiked Silver Peak years ago, the neighbor of Granite Mountain, and I had it in my head that Granite would be similar. It ended up being significantly more work, but also a lot more interesting. Reaching the trailhead is likely possible by any vehicle.
Whiley and I followed the old mining road leading southwest from the trailhead, the same start of the route as you'd take to get up to Silver Peak, but we left this road when our combined guts told us to do so. We were happy with our decision to leave the road when we did; it seemed like had we left any earlier we would have been doing extra bushwhacking, and any later would just have added more distance. The going was slower than we thought it would be heading up the initial slope mostly due to steepness, but the bushwhacking was not bad at all, instead just requiring a little bit of zig-zagging to avoid occasional cacti and brush.
Eventually the slope became significantly less steep and we had a view toward Granite Mountain in the distance, or rather a false summit, but we didn't know that yet. As the slope mellowed out, we were hit with granite boulder obstacles that did require a bit of route-finding to keep the route easier. I'd recommend staying generally left of the ridge crest, dropping lower when necessary, but not too low where the slope appears to get more brushy. Instead, we picked our way through the boulders. On the ascent, we did a few Class 3 moves, but on the way back we somehow made the route easier and managed Class 2. Once out of the bouldery maze, we were at the base of the second major slope ascent, this one a lot more brushy if you stay on the ridge. It will be tempting to stay on the crest, but keep just to the left and locate ample animal/social trails that avoid the majority of the unpleasantness. We didn't find the social trails on the way up, but coming down they were easy to locate and made the route a breeze.
After a bunch of vertical gain, we neared a minor rock outcropping just below the summit, which can be kept Class 2+ by staying to the right. The Granite Mountain summit views were great.
Many people seem to combine the two peaks by following the ridgeline from Granite Mountain over to Silver Peak (or vice versa), but I hear the route is brushy, so the fact it was getting dark didn't make us feel that badly about skipping it (plus I had already gotten Silver and was happy to save my legs the work).